FIGS. 1(a)-(b) show a conventional arrangement of spacers 30, 40 for printed circuit boards incorporated into a meter, such as those used in automotive or vehicular applications for speedometers, tachometers and the like. The components shown in FIGS. 1(a)-(b) comprise three printed circuit boards (PCBs) 20, two opposing spacers 30 bearing grooves 32, a dial spacer 40, and three pushbutton shafts 50.
The uppermost PCB 20, which is disposed adjacent the dial spacer 40, is shown to include a display element (e.g., an LED display) 22, a plurality of shaft contacts or switching elements 24 corresponding in number to the number of pushbutton shafts 50, and a plurality of LEDs 26 disposed about a circumferential portion of the PCB. The LEDs 26 form, in at least some aspects, an arcuate bar graph indicator in which specific LEDs are selectively illuminated in correspondence with an increased magnitude of a measured quantity. One example of this type of indicator is provided in the wide band air/fuel ratio meter manufactured by Auto Meter Products, Inc., of Sycamore, Ill. This meter receives an input signal from a sensor measuring the exhaust gas and, corresponding to an output voltage of the sensor, the sensors are selectively illuminated. For example, a first grouping of LEDs 26 may be selectively illuminated from a specified center point or starting point to indicate a range of acceptable air/fuel ratios, a second grouping of LEDs may be selectively illuminated from a specified center point or starting point to indicate a range of lean air/fuel ratios, and a third grouping of LEDs may be selectively illuminated from a specified center point or starting point to indicate a range of rich air/fuel ratios. Likewise, the display element 22 is configured to display information in a numeric or alphanumeric format to provide information corresponding in type to the gauge. For example, the display element 22 provides information corresponding to the gauge type such as, but not limited to, a peak horsepower, a speed, an acceleration time, a braking distance, G Forces (GS).
Each of the spacers 30 shown in FIGS. 1(a)-(b) comprises three grooves 32, each of the grooves being dimensioned to receive and retain an edge portion of a respective one of the PCBs 20. During manufacture, the spacers 30 are fastened to edges of the PCBs 20, using the grooves 32, in opposition to one another across the PCBs. Following assembly on the PCBs 20, the dial spacer 40 is disposed over the uppermost PCB 20 to space apart the uppermost or outermost PCB 20 from the dial face or window (not shown) of the meter or gauge, as well as to visually segment the light and/or other information output from or printed upon (e.g., numerals) the uppermost PCB. The dial spacer 40 comprises openings 41 for pushbutton shafts 50 or shaft extensions, which are disposed to extend substantially from shaft switching elements 24, through the openings 41 and the dial face or window, and to a position accessible by a user of the meter or gauge.
FIG. 1(b) shows an assembled view of the gauge assembly comprising the above-noted spacers 30 and the dial spacer 40. The pushbutton shafts 50 are inserted into corresponding openings 41 (see FIG. 1(a)) defined within the dial spacer 40 in a location corresponding to the locations of the shaft switching elements 24 on the uppermost PCB 20. The display element 22 is similarly shown in FIG. 1(a) to reside within an opening 44 defined by side walls within the dial spacer 40. The dial spacer 40 further defines a plurality of openings 42 corresponding to the locations of the plurality of LEDs 26 disposed about a circumferential portion of the uppermost PCB 20, shown in FIG. 1(a), to permit transmission of light therethrough.